Any narrowing in the arteries which transport blood to the brain can result in a stroke due to impeded blood flow. Stroke is potentially very damaging to the function of the brain and could lead to paralysis or death. It is the third most common cause of death and the most common cause of disability in the developed world.
Traditional treatments of arterial constrictions involve an open surgical procedure in which the artery is exposed and the surgeon clears the blockage using a procedure called endarterectomy. The morbidity and mortality associated with this technique is high. Hence, minimally invasive techniques have been sought to reduce these complications.
One such minimally invasive technique is percutaneous treatment of blood vessels. Since the introduction of balloons, catheters, and stents, percutaneous treatment of vascular diseases has gained in popularity. These devices have revolutionized treatment of diseases associated with the coronary and other vascular beds in the human body. There are products available to access the coronary arteries in the heart and also the peripheral arteries in the leg through a puncture which is usually made in the femoral artery. Through this puncture, various sheaths, guide wires, guiding catheters are introduced to access a particular section of the artery to be treated using a balloon or a stent.
With the recent advent of non-surgical percutaneous techniques of treating cardiovascular disorders, open surgery is being gradually replaced by non-invasive modes of therapy. In the field of cerebro-vascular diseases, the technology developed for percutaneous coronary artery interventions has been adopted for treating cerebral vessels. For example, Gary Roubin and colleagues have developed a new technique of performing percutaneous cartoid and vertebral artery stenting by the femoral artery route. This technique has been described in a 1996 article published in Circulation.
The safety and efficacy of cartoid and vertebral stenting procedures have been well-established. In addition to these extra cranial procedures, a large number of intra-cranial neurovascular interventions are also being performed all over the world. These intra-cranial interventions include procedures like intracranial angioplasty and stenting, embolic occlusion of arterio-venous malformations and aneurysms, and delivery of intracranial drugs and radiotherapy. A critical part in all of these procedures is obtaining access to the carotid and vertebral arteries by means of guide catheters.
Currently, access to the artery to be treated is obtained by first puncturing the femoral artery in the groin by the Seldinger's technique. A 6 French short sheath is then placed in the created puncture wound. A 5 French diagnostic catheter with a soft guide wire is advanced to engage the origin of the vessel to be treated in the aortic arch. The guide wire is then advanced through the common carotid into the external branch. Next, the diagnostic catheter is advanced over the guide wire which is then exchanged for a stiffer wire. The diagnostic catheter is withdrawn and the 6 French sheath in the femoral artery is also removed.
A long sheath is introduced over the stiff wire and positioned in the carotid artery just proximal to the stenosis. This consists of an outer sheath and a straight introducer tube. The introducer tube is withdrawn once the sheath is placed proximal to the stenosis.
Because the equipment being used for performing carotid and vertebral artery stenting was not originally designed for use in these vessels, there are several deficiencies encountered by interventionists. The most notable of such problems is the lack of an optimal access system. The previously described access procedure is a very lengthy process involving exchange of several guide wires and catheters to obtain access to these supra-aortic vessels. The performance of this complex wire and catheter exchange prolongs the duration of the procedure and also restricts this procedure to only a few experienced interventionists. Even in the hands of an experienced interventionists, vascular anatomical variations make percutaneous treatment of cerebral vessels difficult. There is a risk of air embolism into the cerebral artery in which the exchange takes place. Furthermore, in some cases failure to obtain access to the diseased site leads to an inter-procedural abandonment of the percutaneous technique before treatment.
Thus, there exists a need for an integral access system and method designed specifically for use in the supra-aortic vessels to enhance the ease of the procedure and also ensure greater success of the procedures.